WASHINGTON — After more than 40 years of study, the US government says it has found no evidence that anti-bacterial soaps prevent the spread of germs — and regulators want makers of the products to prove that they do not pose health risks to consumers.

Scientists at the Food and Drug Administration announced Monday that they are revisiting the safety of sanitizing agents found in common household products. Recent studies suggest the substances can interfere with hormone levels in lab animals and spur the growth of drug-resistant bacteria.

The preliminary ruling lends support to outside researchers who have argued that the chemicals are, at best, ineffective and, at worst, a public-health threat.

While the rule only applies to personal-hygiene products, it has implications for a broader $1 billion industry that includes thousands of goods — including toys, pacifiers and toothpaste.

A proposed agency rule will require manufacturers to prove that anti-bacterial soaps are safe and more effective than plain soap and water. Products that are not shown to be safe and effective by late 2016 would have to be reformulated, relabeled or removed from the market.

A spokesman for the American Cleaning Institute said the group will submit new data to regulators, including studies showing that such products do not lead to antibiotic resistance.